Heater Box Removal?

I have my heater box loose in my 69 Dart but I can't get it to clear the dash.
The kickpanel on the right side has been removed and the fan motor and hoses are detached. It seems to be loose enough, just not enough clearance to slide under the dash.
Is there another spot it is attached? It doesn't seem to want to come away from the corner but I can't see anthing still holding it.
Thanks, Kim.